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(1) Field of the Invention
The present invention generally relates to the field of flexible expandable roller conveyors which utilize xe2x80x9clazy tongxe2x80x9d support frames or structures. More particularly, this invention improves upon those conveyors having a plurality of rollers or wheels rotatably impaled upon an axle spanning between two lazy tong lines.
(2) Description of the Related Art Including Information Disclosed Under 37 C.F.R. 1.97 and 1.98
Know in the art are various conveyor systems having expandible flexible systems of rollers or wheels. Typical features include: 1. a plurality of usually parallel horizontal axles, each containing one or more rollers or wheels rotatably impaled thereon; and 2., supporting said axles, a frame system with two parallel lines of scissoring X-shaped pairs of trusses. Each such pair of trusses along each line is pivotally connected at a center point to allow scissoring; moreover, each such scissor-pair along each line (except perhaps at each terminal) is typically pivotally connected at each end (top or bottom) to the corresponding end of an adjacent scissor-pair, thereby forming a chain or line capable of expansion (or contraction) lengthwise by the lengthening (or narrowing) of the distance between the upper ends and lower ends of each scissor-pair apart (or together) in a manner resembling the opening (or closing) of a pair of scissors. Each opposite end of each axle is typically connected to (and supported by) the upper end of at least one (and usually two) scissor-pair, and each axle spans both parallel lazy tong lines.
Each known conveyor system includes additional means of supporting each axle spanning between the lazy tong frame. One known system includes an axle brace member (parallel and below an axle) spanning the outer lazy tong lines. Typically, such an axle brace is essentially a partially inverted U-shaped channel mounted at each end to the upper portion of a scissor-pair truss. In one version wherein each axle impales a plurality of wheels (such as disclosed in U.S. Pat. No. 4,852,712 discussed below), at periodic positions between each wheel (above), the uppermost face of the U-channel includes a plurality of roller support brackets extending upward to the axle, and having a terminal aperture through with the axle is inserted during installation of the wheels. Another known conveyor system (such as depicted on the cover of the Conveyor Price List published by Nestaflex Conveyors, noted below) adds intermediate support to each axle by including additional lazy tong lines between the two outer lazy tong lines. These systems typically have the axle brace attached to a bolt or rod at the center point of a scissor-pair.
For various reasons, impact loading of heavy items causes certain load-bearing parts of the known conveyor systems to buckle, bend, twist or otherwise fail. Under stress, the axle brace may twist or torque, the support bracket may bend or break, the axle may bend, the connection to support legs may be compromised, or any number of similar failures have been known to occur.
The following patents are arguably related to the patentability of the subject invention:
U.S. Pat. No. 4,852,712 issued to Best discloses a conveyor comprising a lazy tong frame system including an outer pair of parallel lazy tong lines and a plurality of multiple-wheeled axles spanning both lazy tong lines, said system supported by a pair of extension legs at both ends. An axle brace (48) spans both lazy tong lines below an associated axle, each end of each axle brace fastened to a scissor-pair truss above the middle pivotal connection of the scissor-pair, so that the vertical orientation of the axle brace varies with the angular positioning of said scissor-pair trusses. Each axle brace includes a plurality of roller support brackets impaled by the axle between adjacent wheels.
U.S. Pat. No. 5,632,371 issued to Best et al. (including the Applicant herein) discloses pairs of vertical bars (42), each bar supporting the end of an axle carrying an elongated roller. An upper portion of each vertical bar is pivotally connected to the adjoining upper ends of adjacent scissor-pairs of a lazy tong line; the top terminus of said vertical bar includes an open-ended upstanding cradle-slot for accepting (in releasable fashion) the terminus of the axle impaling the elongated roller. The primary function of each vertical bar is to provide quick-release attachment of the roller, for quicker maintenance without affecting the connections of adjoining scissor-pairs. The bottom portion of said vertical bar may include an elongated slot, which is impaled (in slidable fashion) by the pin or span-end connecting the adjoining lower ends of said scissor-pairs. Although the upper portion of each vertical bar provides the functional attachment of the axle to lazy tong lines, and thereby provides terminal support for each elongated roller, the lower portion of each vertical bar does not lend strength to the intermediate portion of the axle above (between both terminal ends of the elongated roller); the lower connection occurs only at each point of contact with scissor-pairs of the lazy tong line, so that no support is provided in the middle of the rollers where most of the impact occurs. The slidable lower connection of each vertical bar described in said patent functions to govern expansion and contraction of both lines of the lazy tong frame, which is crucial to prevent malfunctioning of this motorized conveyor; all of the motors mounted coaxial to the middle connection points of the scissor-pairs must constantly maintain the proper distance from the roller axles, to provide the necessary tautness to the pulley belts (between the motor axle and the roller axles) to rotate the rollers. (Column 5, lines 38 to 48.) Even more important, expansion of the lazy tong lines should be limited to assure that at least two motorized axles of rollers are beneath the bottom of the smallest box expected to be conveyed on the conveyor; otherwise, the leading edge of a box traveling along the conveyor may dip into the space between the motorized rollers, and thereby jam the conveyor line (and possibly damage merchandise within the box).
U.S. Pat. No. 5,636,728 issued to Best et al. discloses scissor bars connected to allow expansion or contraction, yet provide vertical support for rollers; perpendicular retaining bars (22) are connected in a sliding relationship to an upper and lower scissor bar connection. These vertical retaining bars support elongated horizontal rollers. However, the lower connection occurs only at each point of contact with a lazy tong structure, so that no support is provided in the middle of the conveyor system where most of the impact occurs.
U.S. Pat. No. 5,224,584 issued to Best et al. (including the Applicant herein) discloses side rollers supported by a brace oriented generally vertically and connected to the top and bottom pivotal connections of a lazy tong line; the bottom portion of the brace contains a slot which receives (in sliding fashion) the fastener that forms the portion of the bottom pivotal connection to the lazy tong line. However, the lower connection occurs only at each point of contact with a lazy tong line, so that no support is provided in the middle of the conveyor system where most of the impact occurs. Moreover, the function of this brace is to hold the side roller in place, and prevent lateral movement thereof rather than providing (or augmenting) the vertical support of the middle portions of the elongated horizontal rollers.
The following publications are arguably related to the patentability of the present invention:
1. Conveyor Price List published by Nestaflex Conveyors.
2. Best, Your Fluid Loading and Unloading Experts (catalog).
The most basic version of the invention disclosed herein is an improved manner of maintaining axle support in an essentially vertical orientation, for optimum load bearing. Ensleeving an axle and extending almost snugly against each wheel hub thereon, there is an axle support having wheel-well cutouts; the axle support is essentially suspended from the ensleeved axle, and extends vertically downward. The axle support terminates in a lower yoke portion through which traverses a lower span (such as a rod connected at each end to a lower end of a scissor-pair on separate lazy tong lines). The axle support may also have a stiffening region (such as, for example, a horizontal V-shaped crease in the span""s planar surface, paralleling the axle), between the yoke portion and the lower end of the wheel-well cutouts. The yoke portion functions primarily to maintain the vertical orientation of the support plane, in optimal load-bearing orientation.
One primary object of the present invention is to provide axle support maintained vertically in optimal load bearing orientation.
Another primary object of the present invention is to provide intermittent intermediate axle support to multiple-wheel axles, between said wheels, maintained vertically in optimal load bearing orientation.
Another object of the invention is to provide axle support having rugged unitary construction.
Another object of the invention is to provide axle support that is relatively easy to manufacture. Another object of the invention is to provide axle support that is relatively inexpensive to manufacture.
Another object of the invention is to provide axle support that is relatively easy to install.
Other objects will be apparent from a reading of the written description disclosed herein, together with the claims.